Resideo at120b1028/u Foot Mounted Transformer 20 Va

Product Description

The RESIDEO at120b1028/u is a foot-mounted, general-purpose step-down transformer designed to supply 24 volt AC power to low-voltage control circuits. Rated at 20 VA with a primary input of 120 volts AC at 60 Hz and a secondary open-circuit voltage of 27 volts, it delivers stable power to thermostats, relays, and other Class 2 control devices. The unit ships with metal end bells installed and connects via leadwire terminations on both the primary and secondary sides. Licensed HVAC technicians and controls specialists are the typical installers for this component.

This transformer is suited for residential and light commercial heating and cooling control systems where a reliable 24 volt AC supply is required. It can also be applied in any general-purpose low-voltage control circuit that does not exceed the 20 VA load rating. The operating temperature range of -20 degrees F to 105 degrees F makes it appropriate for installations in unconditioned mechanical spaces, utility rooms, and equipment closets where ambient temperatures vary seasonally.

Key Features

• 20 VA rating supports standard residential HVAC control loads
• 120 volt AC primary input with 27 volt open-circuit secondary output
• Foot-mount configuration for panel or bracket installation
• Leadwire connections on both primary and secondary sides
• Metal end bells included for mechanical protection
• Meets NEC Class 2 (not wet) and conforms to UL Standard 1585; CSA Certified A and B models

Compatibility

Designed as an OEM-style replacement or new-installation transformer for residential and light commercial HVAC control systems requiring a 120 volt AC primary, 24 volt AC secondary, 20 VA foot-mounted transformer.

Installation Notes

Installation should be performed by a licensed HVAC technician or qualified electrician in accordance with NEC Class 2 wiring requirements. De-energize the circuit at the breaker before connecting or replacing this transformer. Verify that the total connected control load does not exceed the 20 VA rating before powering the circuit. This transformer is rated for indoor, not-wet locations only.

Technical Specifications

• VA Rating: 20 VA
• Primary Input Voltage: 120 volts AC
• Secondary Open Circuit Voltage: 27 volts AC
• Frequency: 60 Hz
• Primary Connection Size: 9 inches
• Secondary Connection Size: 9 inches
• Secondary Connection Type: Leadwires
• Ambient Operating Temperature (Min): -20 degrees F
• Ambient Operating Temperature (Max): 105 degrees F
• NEMA Rating: None
• Approvals and Standards: NEC Class 2, UL Standard 1585, CSA Certified A and B models
• Includes: Metal end bells
• Color: Black, Metallic
• Warranty: 1 Year

Standard Information

• Brand: RESIDEO
• Manufacturer Part Number: at120b1028/u